The present invention relates to an improved heating system for gas heated direct fired center tube revolving ironers. The primary purpose of the invention is to produce a smoothly ironed surface on the laundry work piece. The primary objects sought are to provide an evenly heated roller surface, maximum fuel efficiency and maximum operator safety.
The controlled and uniform heating of the surface of a rotating ironing cylinder has been an industrial control problem since the turn of the century. Many means have been used to provide an even roller surface temperature including steam applied directly into the cylinder, a gas flame inside the hollow cylinder and water jackets inside the cylinder. Many complicated and expensive devices have been used.
The use of a gas flame heating the air in a tube mounted in the center of the roller has proven to be the simplest and most economical approach. Super heated air at high velocity moves down the tube propelled by a gas burner mounted at one end of the roller. This air retains most of the heat imparted by the gas flame causing the entire tube to glow red. The air is then forced back down the cylinder along the inside roller surface exchanging its heat with the ironing surface. The air then exits out the same end of the roller as the burner.
The problems with this simple design include the danger of trapped gas in the roller exploding, inaccurate temperature control of the heating surface by mere modulation of the gas flame for varying loads and inefficient use of the gas with the resultant high cost.